Polybenzoxazole precursors, photoresist solution,...

Details Polybenzoxazole precursors, photoresist solution,... Polybenzoxazole precursors, photoresist solution,...

2001-11-13

2004-11-30

Chu, John S. (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Diazo reproduction, process, composition, or product

Composition or product which contains radiation sensitive...

C430S270100, C430S906000, C528S341000, C528S344000, C528S346000

Reexamination Certificate

active

06824949

ABSTRACT:

BACKGROUND OF THE INVENTION
Field of the Invention
The invention concerns novel polybenzoxazole precursors and resist solutions containing these precursors.
In microelectronics, highly heat resistant polymers are required as protective and insulating layers. These kinds of polymers can be used as a dielectric between two metal planes, e.g. in multi-chip modules and memory and logic chips, or as a buffer coat between the chip and its outline. Some of these polymers, for example precursors of aromatic polyimides (PI) and polybenzoxazoles, are readily soluble in organic solvents, have good film-forming properties and can be applied to the electronic components by means of low-cost centrifugal technique. The precursors are then cyclized through heat treatment, i.e. converted into the corresponding polyimide and polybenzoxazole polymer, and thereby acquire their final properties.
Cyclization results in disappearance of the polar, hydrophilic groups of the PBO precursor (OH, NH and CO), which would otherwise exert a negative influence on the dielectric properties and the water uptake. This is, for example, a significant advantage of polybenzoxazoles in comparison with polyimides and, in particular, in comparison with hydroxypolyimides. However, the cyclization is important not only for the good dielectric properties and the low water uptake of the final product, but also for its high temperature stability.
The specifications for the cyclized final product are very demanding. Thus, for example, in addition to the dielectric constant being as low as possible, the thermal stability must be high.
Polyimides and polybenzoxazoles have the following advantages over many other high-temperature-stable polymers:
In contrast to the cyclized final product, they can be applied to a substrate as a soluble precursor and then cyclized on the substrate, whereby the solubility and therefore the sensitivity towards solvents and other process chemicals is considerably reduced. The processing of pre-cyclized polybenzoxazoles, for example, is difficult for this reason.
Through addition of appropriate photoactive components to the precursors, photosensitive compositions can be produced which enable low-cost direct structuring of the dielectric. Polybenzoxazoles have the further advantage over polyimides that they can be structured in positive mode and developed in aqueous alkali (cf. EP-PS 0 023 662, EP-PS 0 264 678 and EP-PS 0 291 779). For this purpose the PBO precursors used must be soluble in—preferably metal ion free—alkaline developer.
Benzocyclobutene (BCB), which is processed in a similar way and can be negatively structured, has a significantly lower temperature stability than polyimide and polybenzoxazole.
When using polymers of the above kind as a dielectric between metallic conductors it is very important that the metal does not diffuse through the dielectric at elevated temperatures, i.e. at temperatures greater than 300° C. However, many metals, especially aluminum—currently the most commonly used metal—do diffuse through the dielectric at high temperatures. For this reason the metal is provided with a barrier coat, e.g. of titanium nitride or a combination of titanium and titanium nitride, which prevents the diffusion of the metal into the dielectric. However, the use of an additional layer demands a considerably higher outlay of costs and time.
Polybenzoxazole precursors which can be cyclized on substrates and which exhibit good temperature stability are known, for example, from EP-PS 0 023 662, EP-PS 0 264 678, EP-PS 0 291 779, EP-PS 0 905 169, EP-OS 0 905 170 and DE-PS 37 16 629. But there is no information about the diffusion of metals into the polymers prepared from these after cyclization on a substrate (cf. EP-PS 0 264 678 and EP-OS 0 317 942).
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide polybenzoxazole precursors that overcome the above-mentioned disadvantages of the prior art materials, which can be processed by means of the centrifugal technique, which can be cyclized to polybenzoxazoles on substrates without difficulty, and which after cyclization to polybenzoxazoles exhibit a high temperature stability. In particular, these precursors and the polybenzoxazoles prepared from them should possess high resistance against the diffusion of metals.
With the foregoing and other objectives in view there are provided, according to the invention, polybenzoxazole precursors containing one of the following partial structures:
wherein each of A
1
to A
7
is a univalent substituent independently selected from the group consisting of H, F, CH
3
, CF
3
, OCH
3
and OCF
3
;
T is a residue selected from the group consisting of
wherein each of A
8
to A
21
is a univalent substituent independently selected from the group consisting of H, F, CH
3
, CF
3
, OCH
3
and OCF
3
;
wherein X is selected from the group consisting of —CH
2
—, —CF
2
—, —C(CH
3
)
2
—, —C(CF
3
)
2
—, —C(OCH
3
)
2
—, —C(OCF
3
)
2
—, —C(CH
3
)(C
6
H
5
)——C(C
6
H
5
)
2
—, —O—, —(NH)—, —(N—CH
3
)— and —(N—C
6
H
5
)—;
wherein M is selected from the group consisting of residues represented by formulas 10-14
in which Q is selected from the group consisting of C—H, C—F, C—CH
3
, C—CF
3
, C—OCH
3
, C—OCF
3
and N,
and residues represented by formulas 15-34 shown below, in which Q is defined as above, provided that at least one Q signifies N and a maximum of two N atoms are present per ring;
and residues represented by formulas 15-34
wherein Q is defined as above, provided that at least one Q signifies N and a maximum of two N atoms are present per ring.
Dielectrics prepared from polybenzoxazole precursors of this kind exhibit, in particular, a significantly reduced aluminum diffusion. As a result, an additional barrier layer is superfluous.
The metal diffusion can then be reduced still further if acetylene groups are integrated into the precursor molecules. These acetylene groups can be present in the main chain of the precursor molecules, as a terminal group of a precursor molecule, or as a side chain of a precursor molecule.
Preferably the acetylene group is contained in one of the following compounds:
With the foregoing and other objectives in view there are also provided, according to the invention processes for preparing polybenzoxazole precursors with the above structure by a self-condensation reaction of an appropriate o-aminophenolcarboxylic acid and by reaction of appropriate bis-o-aminophenols or o-aminophenolcarboxylic acids—whereby in each case one or several of these compounds can be used—with one or more suitable dicarboxylic acid compounds such as dicarboxylic acids and dicarboxylic acid derivatives, in particular active esters and chlorides. Active esters of dicarboxylic acids include, for example, the methyl, t-butyl, and phenyl esters. For this purpose the bis-o-aminophenol or o-aminophenolcarboxvlic acid and the dicarboxylic acid or dicarboxylic acid derivative, when present, are reacted together, suitably in an organic solvent at a temperature from −20 to 150° C., and the resulting polymer precipitated by adding the reaction mixture dropwise to a suitable precipitating agent. The precipitated polymer can be used immediately after being filtered off and dried. Before the precipitation of the polymer, its terminal amino groups can be protected, i.e. blocked, using a dicarboxylic acid anhydride or a monocarboxylic acid chloride. The o-aminophenolcarboxylic acids can also be reacted alone, i.e. without a dicarboxylic acid.
The bis-o-aminophenols and o-aminophenolcarboxylic acids used for preparation of the polybenzoxazole precursors according to the invention have the following respective structures:
in which A
1
-A
3
, A
4
-A
7
, and T are as defined above.
These compounds are the subject of German patent application submitted at the same time: File No.
“Bis-o-aminophenols and o-aminophenolcarboxylic acids” (GR 00 P 8529 DE).
The designations “A
1
-A
3
”, “A
4
-A
7
”, “A
8
-A
10
”, “A
11
-A
14
”, “A
15
-A
17
” and “A
18
-A
21
” in the structural formulae mean that the

Affiliated with

Also associated with

Rating

Polybenzoxazole precursors, photoresist solution,... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Polybenzoxazole precursors, photoresist solution,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polybenzoxazole precursors, photoresist solution,... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3358449